Dodging/Rolling Tips?

Anyone have any tips on how to add Dodging/Rolling into your game? Currently I am just beating on people constantly and don't do many defensive maneuvers. I know I need to learn this in order to get better. Thanks!

I don't EVER use the air dodge...it nullifies aerial smashes, which I love
it depends on your controller; with a GC controller, I use the R button and the direction to roll because you use L with the same hand as the control stick which throws off my timing
I use my right hand for everything but directions...I jump with Y
Also, you need to time the rolls correctly-like dws said, you avoid the strong attack then strike during the recovery using the roll
but you need to know when you need to roll or strike and time it correctly
and exploit your enemy's weaknesses to the fullest extent-e.g.: if they're bad at aerials, use more aerials